1. Field of the Invention
The present invention relates to a chroma key signal generator for a video editing apparatus, and more particularly to a chroma key signal generator which enables the chroma key signal to be obtained from a composite video signal.
2. Description of the Prior Art
In general, a chroma key apparatus which is a kind of video editing apparatus includes a chroma key signal generator for providing a chroma key signal in response to specific hues of the chrominance signal of the color video signals, and a selection switch for selecting one among two or more chrominance signals according to this key signal, so that two or more color video signals can be mixed.
In the conventional chroma key signal generator of the above type, the chroma key signal is generated by utilizing three primary color signals of red(R), green(G) and blue(B). However, it is not possible to use the chroma key signal generators for VCRs and/or a color TV set as the primary color signals R, G and B are not attainable in the video cassette recorder or the color TV set which process the composite video signals as color difference signals. Accordingly, at least one additional video camera is required to generate a chroma key signal, and thereby the conventional chroma key signal generators are subjected to restriction in use.